JPS5850920B2 - boat propeller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally includes a propelling vane, which is rotated by the operation of a driving source to propel a gaseous or liquid medium around the vane, or rotated by the force of the flow of the surrounding medium. The present invention relates to such propulsion and rotation devices, particularly propellers for watercraft.

Conventionally, existing propellers are provided with propulsion blades having a permanently fixed pitch, but these have the drawbacks of low propulsion efficiency and inability to transmit the maximum output of the engine (prime mover).

In order to eliminate the above-mentioned drawbacks of existing propellers, propellers have been manufactured that have blades whose pitch can be adjusted so that the pitch can be automatically increased as the speed increases.

With this method, it became possible to increase the propulsion efficiency only while the propeller was rotating with acceleration, but at the same time, the engine during accelerated operation suddenly reached its maximum rotational speed (r, p). , m), it has fallen into a defect in which the maximum torque of the engine cannot be transmitted by the propeller.

An object of the present invention is to provide a propeller capable of transmitting full power no matter what speed the watercraft is traveling at.

According to the present invention, the hub and the first
A watercraft propeller having a set of blades and a second set of blades, the first set of blades having a permanently fixed pitch and the second set of blades having a variable pitch, the second set of blades being rotatable on a hub. To achieve the above object by providing each vane with its axis of rotation on the pressure side of the vane such that the blade is pivoted to the blade and its pitch is adjusted only by the rotational speed of the hub and the axial velocity of the water flow around the blade. I can do it.

That is, in the present invention, since the second set of variable pitch blades is rotatably pivoted to the hub and has its rotation axis on the pressure side of each blade (concave side of the blade), it is possible to change the pitch. The pitch is automatically changed according to the rotational speed of the hub and the axial velocity of the water flow around the blades without the need for a control device, so full power can be transmitted at all cruising speeds, and the construction is extremely simple. It's easy.

Next, the propulsion and rotation device according to the present invention will be described in detail with reference to the illustrated embodiments.

The simple diagrams of FIGS. 1 and 3 show various load curves F1 to F3 obtained experimentally using a conventional propeller with a permanently fixed pitch.

To briefly explain the above chart, the load curve F1~
F3 represents the prime mover (engine) load at various constant speeds, of which the load curve F1 represents the prime mover load when the boat is stationary, F3 represents the maximum speed of the boat, and F2 represents the load at intermediate speeds. The figure shows the prime mover load for each vehicle.

During accelerated sailing of a boat fitted with a propeller with permanently fixed blades, i.e. during low speed sailing with the gas supply valve fully open, the propulsion blades of the propeller operate at a large angle of attack.

Without it, the propeller experiences strong resistance underwater.

Propellers that are subject to this type of action generally utilize the maximum torque of the engine, but the structure is such that the engine rotational speed (r, p, m, ) at maximum torque cannot reach even 60% of the maximum rotational speed. It has become.

In the above explanation, as shown in the load curve F1 in the diagram, the maximum torque is first obtained during acceleration cruising, and then as the cruising speed of the watercraft increases, the engine rotational speed also increases.

Maximum power is therefore generated while the watercraft is traveling at maximum speed, as shown by load curve F3.

When traveling at low speeds, for example when towing another watercraft, the full power cannot be transmitted and the engine cannot reach its maximum speed, as is clear from the diagram.

The propeller shown in FIG. 2 has the opposite performance as the propeller described above.

That is, a plurality of propulsion blades 10 (only one of which is shown in the figure) provided on the propeller are rotated by the bub 1 by bearings 12.
It is rotatably pivoted to 1.

As shown in the figure, a bearing 12 pivotally connects the blade 10 to the bub via an arm 13 formed at the inner edge of the blade 10.

In practice, the vane itself can be bent at its inner edge to form a bent section similar in shape to the arms described above.

The bearing 12 described above is mounted on or near the rotation axis 14 of the bubble 11.

Since the propeller blades themselves automatically adjust, the propeller has the characteristic that the angle of attack relative to the flow direction of the working medium is always constant.

Therefore, the pitch of the propulsion blades changes depending on the relationship between the engine rotation speed and the boat's cruising speed.

However, the propulsion blades of the propeller can rotate extremely easily, and when the gas supply valve is fully opened and acceleration is applied, the engine reaches its maximum rotation speed, but the propeller cannot transmit the maximum torque. .

The above explanation is made clear by the load curve L1 in the load diagram shown in FIG. 3, which corresponds to the diagram in FIG.

Load curve L1 shows the load when the boat is stationary, L3 shows the load when the boat is at the maximum speed, and L2 shows the load when the boat is sailing at an intermediate speed.

As the cruising speed of the watercraft increases, both the pitch and the transmitted torque of the variable vanes increase, so that maximum power can be obtained while cruising at maximum speed.

During accelerated navigation, the propeller described above provides much greater propulsive efficiency than conventional propellers with fixed blades, but the maximum thrust of the propeller is also reduced because less force is transferred from the engine to the water.

FIG. 4 is a plan view showing an embodiment of the propeller according to the present invention, and this propeller has the above-mentioned fixed pitch blades and the blades shown in FIG. By combining these propellers, it is possible to eliminate the above-mentioned drawbacks of each propeller.

In the figure, the same parts as shown in FIG. 3 are given the same reference numerals, and their explanations will be omitted.

This propeller has a bub 11 rotatably supported by a bearing 12.
It consists of one blade 10 that is pivotally supported by the blade 10, and one fixed blade 15 that is fixed to the bub 11 on the opposite side of the blade 10.

Alternatively, both vanes 10 and 15 may be attached to separate bubs that are arranged on the same axis at different axial positions.

The adjustable blade 10, which can adjust the pitch by itself, is already known and of the type described above. The angle of attack is formed vectorially by the rotational speed of the propeller and the axial speed of the water flow, that is, the speed of the boat.

In this manner, when the axial flow velocity is low, the adjustable pitch blades 10 self-adjust with a small pitch.

At this time, the pitch of the fixed blade 15 is approximately the same as the pitch adjusted by the variable pitch blade 10 at the maximum rotational speed of the propeller and the maximum speed of the watercraft.

Even more generally, when the relationship between the axial flow speed and the rotational speed becomes equal to the relationship between the maximum axial flow speed and the maximum rotational speed, the pitches of the fixed blades 15 and the adjustable pitch blades 10 become approximately equal.

If the total blade area of the fixed blades and adjustable pitch blades is selected in an arbitrary relationship, the combination of propellers that can transmit the full power of the engine when the boat is stationary, when the boat can reach its maximum speed, and when the boat is stationary, respectively. can get.

An example of such a combination is shown in the diagram of FIG.

The intermediate line M1 in the chart shows the motor load when the boat is stationary, and the curve M2 shows the motor load when the boat reaches its maximum speed.

The diagram also shows that for all intermediate speeds, the full power can be transmitted more or less completely.

The relationship between the combined area of the blades is fundamentally determined by the relationship between the rotational speed and the number of revolutions per minute of the force generated by the direction of rotation of the blades on water.

In order to obtain a propeller with optimal dimensions, the total area of the blades that can be adjusted in pitch should be 60 to 85 of the total area of all blades.
The proportion is high, preferably 70%.

FIG. 6 is a perspective view showing another embodiment of the propeller according to the invention, in which two blades 21 having a permanently fixed pitch and two adjustable blades 23 whose pitch can be automatically adjusted as described above are shown. They are provided on the bubbles 20 alternately.

Here, the blade 23 is rotatably mounted on the bub 20 by a bearing 22.

FIG. 7 shows another embodiment of the propeller according to the present invention, in which three blades 32 whose pitch can be automatically increased or decreased and three fixed blades 31 are alternately provided on a bub 30.

In this embodiment, the shape of each vane resembles a wing with flaps.

The invention has the advantage that the maximum speed of a watercraft is less influenced by, for example, weather, wind, etc., and at the same time the time required for acceleration is reduced, especially for rowing boats that float out of the water or the like. The above-mentioned advantages are remarkable for fast boats.

Especially in low-speed navigation, it can provide greater thrust to trawlers, training boats, etc., and it is also cheaper to manufacture than propellers whose blades are mechanically modified to change the pitch. with the benefits of becoming.

In the diagram of Figure 5, the propeller, which is fundamentally dependent on the speed of the boat, loads the engine with torque, except when operating in the lowest speed range, and fundamentally increases the speed of the engine. Multiply by 4.

This eliminates the need for the engine to have such a strong torque at low rotational speeds, and the maximum torque is only used to accelerate the inertial mass of the propeller.

Therefore, a single-shaft gas turbine engine can be used for the propeller.

The principle of the present invention is not limited to the embodiment shown in FIGS. 6 and 7 in which the fixed vane and the adjusting vane are disposed in the same bubble; It also includes propellers spaced apart from each other in the bubbles.

That is, the separate bubs may be provided at different axial positions on the same shaft, or may be mounted on separate shafts, each driven by the engine at the same speed or at different speeds.

In the latter case, since the pitch can be adjusted to correspond to different speeds, for example, a propeller rotating at a slower speed than one can be adjusted to a pitch corresponding to that speed.

Although the invention has been described above with respect to a propeller for a watercraft, it may also be applied to rotating devices for rotating blades to drive a surrounding medium, such as turbine impellers, impeller pump impellers, etc., and vice versa. It can also be applied to rotating devices where the impeller rotates.

FIG. 8 schematically shows a part of a turbine impeller or impeller 40, which has one fixed blade 41 and two adjustable blades 42 arranged alternately in a row. be.

Alternatively, the impeller may be provided with fixed blades arranged in one row, and adjustable blades arranged in another row spaced apart from the fixed blade row in the axial direction.

In the same way as described in connection with the propeller, fixed blades and adjustable blades can also be arranged on separate impellers.

[Brief explanation of drawings]

Figure 1 is a diagram depicting the various prime mover (engine) load curves that occur when using a conventional propeller with a permanently fixed pitch; Figure 2 is a diagram depicting the propeller bub and self-adjustable blade airfoils; FIG. 3 is a diagram depicting various motor load curves corresponding to FIG. 1 when the propeller shown in FIG. 2 operates, and FIG. 4 shows an embodiment of the propeller according to the present invention. A plan view, FIG. 5 is a chart depicting various motor load curves corresponding to FIG. 1 when the propeller of FIG. 4 constructed based on the principle of the present invention operates, and FIG. FIG. 7 is a perspective view showing another embodiment of the propeller according to the present invention, FIG. 8 is a perspective view showing a part of the turbine impeller according to the present invention. It is. Symbols in the figure: 10, 23, 32, and 42... Rotatable and pitch-adjustable blades, 11, 20° 30 and 40... Hub, 12, 22... ··bearing,
13...Arm part, 14...Rotation axis line, 1
5,21.31 and 41...Fixed blades.

Claims (1)

[Claims] 1. In a watercraft propeller having a hub and a first set and a second set of blades attached to the hub, the first set of blades having a permanently fixed pitch and the second set of blades having a variable pitch. , the second set of vanes is rotatably pivoted to the hub, and each vane has its rotation on the pressure side of the vane such that its pitch is adjustable only with respect to the rotational speed of the hub and the axial velocity of the water flow around the vanes. A boat propeller characterized by having a shaft.